19 is only 1 away from 20, so you prefer to start by multiplying 20 times 5, which equals 100. Then we need to take away a squadron of 5, because there are actually only 19 squadrons, not 20. 100 take ...

This summer, battle lines were drawn over a simple math problem: 8 ÷ 2(2 + 2) = ? If you divide 8 by 2 first, you get 16, but if you multiply 2 by (2 + 2) first, you get 1. So, which answer is right?

Knowing your multiplication facts is very useful, but what happens when the numbers you are multiplying are greater than those in your multiplication tables? You will need to calculate using a column ...

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. It's called the Gelosia method and it uses a crosshatch, or lattice template, to multiply large numbers ...